xss-lock: add patch to allow setting session

[offlinehacker]

Motivation for this change

xss-lock uses current session that cannot be overriden. This prevents starting
xss-lock as systemd user service, as described here:
https://bitbucket.org/raymonad/xss-lock/issues/13/allow-operation-as-systemd-user-unit

This change adds additional patch that adds --session parameter. I decided not to use fetchPatch, as we do not want to depend on unofficial repos.

Thanks @xdbob for initial implementation here: https://github.com/xdbob/xss-lock

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• x ] Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[offlinehacker]

@uvNikita decided to make a patch to address this issue: https://github.com/rycee/home-manager/blob/master/modules/services/screen-locker.nix#L70 so we can make a systemd user service.

[uvNikita]

Nice, would be great to get a fix for it!

The patch looks small enough to me, but I'm not sure what's recommended here for custom patches like this.

Also, I don't understand where does GRAPHICAL_SESSION_ID come from? Who is supposed to set it?

[offlinehacker]

Well this patch should be upstreamed anyway, but I do not know what happened with the project as last commit is from 2014. Do you know any other alternative to xss-lock? Also GRAPHICAL_SESSION_ID should be XDG_SESSION_ID, will fix that.

[xdbob]

@offlinehacker I don't want to be a d*ck but could you at least mention where the code is comming from in the commit message ? It would be greatly appreciated :)

As for GRAPHICAL_SESSION_ID it was meant not to be XDG_SESSION_ID since each session has a session id, it was meant to be the session id tied to the graphical-session.target and imported by whoever would bring the target up

[offlinehacker]

Thanks for explanation @xdbob and sorry I forgot to mention you in commit. I think the best course would be to just change source to @xdbob fork. At least one other distro uses it: https://aur.archlinux.org/packages/xss-lock-session/ If for some reason it gets removed we can fix later.

[offlinehacker]

Ok, i changed source to use @xdbob fork. I do not think we need two packages for that, as it's minimal change, that does not break any additional functionality and i think it would be also easier to introduce new changes to this new repo.

[uvNikita]

Looks good to me

[xdbob]

And by the way, if you are interested in the feature I have a branch keeping the logind's LockedInt status up to date: https://github.com/xdbob/xss-lock/tree/locked_hint

I can also tag a release for the occasion (I used master for months without issue).

PS: I don't use xss-lock anymore (wayland <3) but if someone is willing to test the patches I am willing to keep maintaining it and reviewing the patches

[offlinehacker]

Thanks @xdbob, for now I will just accept master branch, but I will review and test locked_hint branch and can be later merged to master. Having a tag would be also really nice(after locked_hint branch is merged), thanks again 🙂